Transmitting/receiving apparatus and a transmitting/receiving method

ABSTRACT

A security apparatus and a security method for controlling electric devices by use of electronic mails. A modem receives an electronic mail sent from a sending side and stores the received electronic mail into a RAM of a controller. A CPU extracts certification information encrypted by a secret key of a user of the sending side and decrypts the certification information by use of a public key. Based on the decrypted information, the CPU determines whether the user of the sending side is authentic or not. Only when the user is found authentic, the CPU extracts a control command from the received electronic mail and stores the extracted control command into a RAM. Then, the CPU transmits an electronic mail to the sending side for confirming content of the control. If an electronic mail for approving the confirmation is returned from the sending side, the CPU extracts second certification information obtained by encrypting information different from that mentioned above, determines again whether the sender of the electronic mail is authentic, and, if the sender is found authentic, executes the control command received before.

BACKGROUND OF THE INVENTION

The present invention generally relates to a receiving apparatus, areceiving method, a transmitting apparatus, a transmitting method, atransmitting/receiving apparatus, and a transmitting/receiving methodand, more particularly, to a receiving apparatus, a receiving method, atransmitting apparatus, a transmitting method, a transmitting/receivingapparatus, and a transmitting/receiving method that allow connectionthrough a network.

Related art consumer electronics such as television receivers and videodecks are controlled by operating controls arranged on the main framesor remote commanders of these devices.

It is also practical for a user to control related art consumerelectronics by use of a timer capability that executes a controloperation at any time preset by the user.

Recently, a home video deck for example can be controlled from outsidehome in a so-called interactively manner by use of a telephone tonesignal.

However, the electric devices that are controlled by operating thecontrols attached on these electronic devices or on the remotecommanders thereof do not allow the user to control them if the user isaway from home.

Further, even if an electric device is equipped with a timer, the samegenerally cannot be controlled from outside home, thereby disabling theuser to cope with unexpected situations in which something emergenthappened.

Still further, in controlling electric devices in an interactive mannerby use of telephone line, it is necessary to operate controls inresponse to a voice sent from the receiving side (namely, an electricdevice), thereby presenting a problem of taking time. If a plurality ofelectric devices are installed in a home, attempting to control each ofthem in the same manner requires to assign each to a telephone line,thereby presenting a problem of increasing facilities cost.

To circumvent these problems, a method may be employed in which anelectronic mail attached with a control command is sent to the receivingside and the same controls a specified electronic device based on thecontrol command.

However, it is difficult for this method to certify whether the personwho sent the electronic mail is an authentic user or not, therebypresenting a problem that the security of the device to be controlledcannot be ensured.

If a plurality of authentic users exist, it presents another problemthat received control commands may be duplicate or contradictory to eachother.

It is therefore an object of the present invention to enhance, whencontrolling electric devices by electronic mail, security of theelectric devices under control and perform correct control thereon.

SUMMARY OF THE INVENTION

In carrying out the invention and according to a first aspect thereof,there is provided a receiving apparatus. In this receiving apparatus, areceiving means receives an electronic mail coming through a network. Afirst extracting means extracts encrypted certification information fromthe electronic mail received by the receiving means. A second extractingmeans extracts a control command for controlling a predeterminedelectric device from the electronic mail received by the receivingmeans. A decrypting means decrypts the certification informationextracted by the first extracting means. A certifying means certifies,by referencing the certification information decrypted by the decryptingmeans, whether a sender of the electronic mail is an authentic user ornot. If the sender of the electronic mail is found an authentic user, astoring means stores the control command extracted by the secondextracting means. For example, the receiving means receives anelectronic mail coming over the Internet. The first extracting meansextracts, from received the electronic mail, certification informationgenerated by encrypting predetermined text information by use of asecret key. The second extracting means extracts a control command forcontrolling a video deck for example. The certification informationextracted by the first extracting means is decrypted by use of a publickey. Based on the decrypted certification information, the certifyingmeans determines whether the sender of the electronic mail is anauthentic user. If the send is found an authentic user, the storingmeans stores the control command extracted by the second extractingmeans.

In carrying out the invention and according to a second aspect thereof,there is provided a receiving method. In this receiving method, areceiving step receives an electronic mail coming through a network. Afirst extracting step extracts encrypted certification information fromthe electronic mail received by the receiving step. A second extractingstep extracts a control command for controlling a predetermined electricdevice from the electronic mail received by the receiving step. Adecrypting step decrypts the certification information extracted by thefirst extracting step. A certifying step certifies, by referencing thecertification information decrypted by the decrypting step, whether asender of the electronic mail is an authentic user or not. If the senderof the electronic mail is found an authentic user, a storing step storesthe control command extracted by the second extracting step. Forexample, the receiving step receives an electronic mail coming over theInternet. The first extracting step extracts, from received theelectronic mail, certification information generated by encryptingpredetermined text information by use of a secret key. The secondextracting step extracts a control command for controlling a video deckfor example. The certification information extracted by the firstextracting step is decrypted by use of a public key. Based on thedecrypted certification information, the certifying step determineswhether the sender of the electronic mail is an authentic user. If thesend is found an authentic user, the storing step stores the controlcommand extracted by the second extracting step.

In carrying out the invention and according to a third aspect thereof,there is provided a transmitting apparatus. In this transmittingapparatus, an electronic mail inputting means inputs an electronic mail.An encrypting means encrypts predetermined information. A first addingmeans adds, as certification information, the information encrypted bythe encrypting means to the electronic mail inputted by the electronicmail inputting means. A second adding means adds a control command forcontrolling a predetermined electric device to the electronic mailinputted by the electronic mail inputting means. A transmitting meanstransmits through a network the electronic mail with the certificationinformation added by the first adding means and the control commandadded by the second adding means. For example, the electronic mailinputting means input an electronic mail. The encrypting means encryptspredetermined text information included in the electronic mail. Thefirst adding means adds, as certification information, the textinformation encrypted by the encrypting means to the electronic mailinputted by the electronic inputting means. The second adding means addsa control command for controlling a video deck for example to electronicmail. The transmitting means transmits over the Internet the electronicmail with the certification information added by the first adding meansand the control command added by the second adding means.

In carrying out the invention and according to a fourth aspect thereof,there is provided a transmitting method. In this transmitting method, anelectronic mail inputting step inputs an electronic mail. An encryptingstep encrypts predetermined information. A first adding step adds, ascertification information, the information encrypted in the encryptingstep to the electronic mail inputted in the electronic mail inputtingstep. A second adding step adds a control command for controlling apredetermined electric device to the electronic mail inputted in theelectronic mail inputting step. A transmitting step transmits through anetwork the electronic mail with the certification information added inthe first adding step and the control command added in the second addingstep. For example, the electronic mail inputting step input anelectronic mail. The encrypting step encrypts predetermined textinformation included in the electronic mail. The first adding step adds,as certification information, the text information encrypted in theencrypting step to the electronic mail inputted in the electronicinputting step. The second adding step adds a control command forcontrolling a video deck for example to electronic mail. Thetransmitting step transmits over the Internet the electronic mail withthe certification information added in the first adding step and thecontrol command added in the second adding step.

In carrying out the invention and according to a fifth aspect thereof,there is provided a transmitting/receiving apparatus. In a transmittingside of this transmitting/receiving apparatus, an electronic mailinputting means inputs an electronic mail. An encrypting means encryptspredetermined information. A first adding means adds, as certificationinformation, the information encrypted by the encrypting means to theelectronic mail inputted by the electronic mail inputting means. Asecond adding means adds a control command for controlling apredetermined electric device to the electronic mail inputted by theelectronic mail inputting means. A transmitting means transmits over anetwork the electronic mail with the certification information added bythe first adding means and the control command added by the secondadding means. In a receiving side of this transmitting/receivingapparatus, a receiving means receives the electronic means transmittedover the network. A first extracting means extracts the certificationinformation from the electronic mail received by the receiving means. Asecond extracting means extracts the control command from the electronicmail received by the receiving means. A decrypting means decrypts thecertification information extracted by the first extracting means.Referencing the certification information decrypted by the decryptingmeans, a certifying means certifies whether a sender of the electronicmail is an authentic user. If the sender of the electronic mail is foundan authentic user, a storing means stores the control command extractedby the second extracting means. For example, in the transmitting side,the electronic mail inputting means inputs an electronic mail. Theencrypting means encrypts predetermined text information included in theelectronic mail. The first adding means adds, as certificationinformation, the information encrypted by the encrypting means to theelectronic mail inputted by the electronic mail inputting means. Thesecond adding means adds a control command for controlling a video deckfor example to the electronic mail. The transmitting means transmitsover the Internet the electronic mail with the certification informationadded by the first adding means and the control command added by thesecond adding means. In the receiving side, the receiving means receivesthe electronic mail coming over the Internet. The first extracting meansextracts certification information generated by encrypting predeterminedtext information by use of a secret key from the received electronicmail. The second extracting means extracts a control command forcontrolling a video deck for example from the received mail. Thedecrypting means decrypts, by use of a public key, the certificationinformation extracted by the first extracting means. Referencing thedecrypted certification information, the certifying means certifieswhether a sender of the electronic mail is an authentic user. If thesender is found an authentic user, the storing means stores the controlcommand extracted by the second extracting means.

In carrying out the invention and according to a fifth aspect thereof,there is provided a transmitting/receiving method. In a transmittingside of this transmitting/receiving method, an electronic mail inputtingstep inputs an electronic mail. An encrypting step encryptspredetermined information. A first adding step adds, as certificationinformation, the information encrypted in the encrypting step to theelectronic mail inputted in the electronic mail inputting step. A secondadding step adds a control command for controlling a predeterminedelectric device to the electronic mail inputted in the electronic mailinputting step. A transmitting step transmits over a network theelectronic mail with the certification information added in the firstadding step and the control command added in the second adding step. Ina receiving side of this transmitting/receiving method, a receiving stepreceives the electronic step transmitted over the network. A firstextracting step extracts the certification information from theelectronic mail received in the receiving step. A second extracting stepextracts the control command from the electronic mail received in thereceiving step. A decrypting step decrypts the certification informationextracted in the first extracting step. Referencing the certificationinformation decrypted in the decrypting step, a certifying stepcertifies whether a sender of the electronic mail is an authentic user.If the sender of the electronic mail is found an authentic user, astoring step stores the control command extracted in the secondextracting step. For example, in the transmitting side, the electronicmail inputting step inputs an electronic mail. The encrypting stepencrypts predetermined text information included in the electronic mail.The first adding step adds, as certification information, theinformation encrypted in the encrypting step to the electronic mailinputted in the electronic mail inputting step. The second adding stepadds a control command for controlling a video deck for example to theelectronic mail. The transmitting step transmits over the Internet theelectronic mail with the certification information added in the firstadding step and the control command added in the second adding step. Inthe receiving side, the receiving step receives the electronic mailcoming over the Internet. The first extracting step extractscertification information generated in encrypting predetermined textinformation in use of a secret key from the received electronic mail.The second extracting step extracts a control command for controlling avideo deck for example from the received mail. The decrypting stepdecrypts, in use of a public key, the certification informationextracted in the first extracting step. Referencing the decryptedcertification information, the certifying step certifies whether asender of the electronic mail is an authentic user. If the sender isfound an authentic user, the storing step stores the control commandextracted in the second extracting step.

According to the receiving apparatus and the receiving method associatedwith the present invention, an electronic mail transmitted over anetwork is received. Encrypted certification information is extractedfrom the received electronic mail. A control command for controlling apredetermined electric device is extracted from the received electronicmail. The extracted certification information is decrypted. Thedecrypted certification information is referenced to certify whether asender of the electronic mail is an authentic user. If the sender isfound an authentic user, the extracted control command is stored. Thisnovel constitution allows only the information sent from an authenticuser to be received for storage.

According to the transmitting apparatus and the transmitting methodassociated with the present invention, an electronic mail is inputted.Predetermined information is encrypted. The encrypted information isadded, as certification information, to the inputted electronic mail. Acontrol command for controlling a predetermined electric device is addedto the inputted electronic mail. The electronic mail added with thecertification information and the control command is transmitted. Thisnovel constitution allows the receiving side to easily and reliablydetermine whether the sender of the electronic mail is an authentic useror not.

According to the transmitting/receiving apparatus and thetransmitting/receiving method associated with the present invention, inthe transmitting side, an electronic mail is inputted. Predeterminedinformation is encrypted. The encrypted information is added to theinputted electronic mail as certification information. A control commandfor controlling a predetermined electric device is added to the inputtedelectronic mail. The electronic mail added with the certificationinformation and the control command is transmitted over a network. Inthe receiving side, the electronic mail coming over the network isreceived. The certification information is extracted from the receivedelectronic mail. The control command is extracted from the receivedelectronic mail. The extracted certification information is decrypted.Based on the decrypted certification information, it is determinedwhether the sender of the electronic mail is an authentic user. If thesender is found an authentic user, the extracted control command isstored. This novel constitution allows the receiving side to determine,based on the certification information added to the electronic mail atthe sending side, whether the sender is an authentic user, therebyextracting the control command from the electronic mail for storage onlywhen the sender is found an authentic user.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the invention will be seen by reference tothe description, taken in connection with the accompanying drawing, inwhich:

FIG. 1 is a schematic diagram illustrating, by way of example, aconstitution of a preferred embodiment of the invention;

FIG. 2 is a block diagram illustrating, by way of example, a detailedconstitution of a terminal 1-1 shown in FIG. 1;

FIG. 3 is a block diagram illustrating, by way of example, a detailedconstitution of a terminal 1-4 shown in FIG. 1;

FIG. 4 is a diagram illustrating, by way of example, a display screen inwhich an electronic mail is inputted;

FIG. 5 is a flowchart for describing, by way of example, processing tobe performed when the electronic mail input screen shown in FIG. 4 isdisplayed.

FIG. 6 is a diagram illustrating, by way of example, an electronic mailwhich is generated when “OK” button is pressed in the input screen shownin FIG. 4;

FIG. 7 is a flowchart for describing, by way of example, processing tobe performed in the terminal 1-1 when the electronic mail shown in FIG.6 is received;

FIG. 8 is a diagram illustrating, by way of example, an electronic mailto be sent if it is indicated in the flowchart shown in FIG. 7 thatreservation is disabled;

FIG. 9 is a diagram illustrating, by way of example, an electronic mailto be sent when temporary reservation has been completed in theflowchart shown in FIG. 7;

FIG. 10 is a flowchart for describing, by way of example, processing tobe performed when the terminal 1-4 receives an electronic mail forconfirming setting to be sent upon establishment of certification afterexecution of the processing shown in FIG. 7;

FIG. 11 is a diagram illustrating, by way of example, a screen to bedisplayed on CRT monitor 25 of the terminal 1-4 when the processingshown in FIG. 10 has been executed;

FIG. 12 is a diagram illustrating, by way of example, an electronic mailto be sent when “SEND” button is pressed in the display screen shown inFIG. 11;

FIG. 13 is a flowchart for describing, by way of example, processing tobe executed in the terminal 1-1 when the electronic mail shown in FIG.12 is received;

FIG. 14 is a diagram illustrating, by way of example, an electronic mailto be sent when reservation has been completed in the flowchart shown inFIG. 13;

FIG. 15 is a flowchart for describing, by way of example, a sequence ofprocessing operations for reserving recording on video deck 27; and

FIG. 16 is a flowchart for describing, by way of example, processing tobe executed in the terminal 1-1 when reservation for recording has beenperformed by electronic mail.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

This invention will be described in further detail by way of examplewith reference to the accompanying drawings.

Now, referring to FIG. 1, there is shown a schematic view of aconstitution of a preferred embodiment of the invention by way ofexample. In the figure, terminals 1-1 through 1-3 and 1-4 through 1-6are connected to providers 3-1 and 3-2 over public telephone lines 2-1and 2-2 (analog lines or ISDN (Integrated Services Digital Network)lines for example) respectively. Under the control of the providers 3-1and 3-2, these terminals can transfer information with each other.

The providers 3-1 and 3-2 are adapted to establish connection based onTCP/IP (Transmission Control Protocol/Internet Protocol), namely dial-upIP connection, with any of the terminals 1-1 through 1-6 when the samecalls the corresponding provider over the corresponding public telephoneline 2-1 or 2-2.

The Internet 4 interconnects the providers 3-1 and 3-2 and communicatesinformation therebetween based on the above-mentioned TCP/IP.

Referring to FIG. 2, there is shown a block diagram illustrating anelectrical constitution of the terminal 1-1 shown in FIG. 1 byway ofexample. As shown in FIG. 2, a gateway 20 transfers information withother terminals over the public telephone 2-1.

An input block 24 is composed of a keyboard and a mouse for example andoperated to input predetermined information into the gateway 20. A CRT(Cathode Ray Tube) Monitor 25 is adapted to display received informationand the information inputted from the input block 24.

An IR (InfraRed) transmitter 26 radiates infrared ray under the controlof the gateway 20 to control a video deck 27.

A connection cable 28 is a signal line based on a home bus such as WiredCIRCS or LANC (a local bus for interrelating a plurality of videodevices for example for controlling the same) and adapted to transferinformation between the gateway 20 and the video deck 27. The video deck27 is adapted to perform operations such as recording, reproducing, andstop according to a control signal transmitted through the IRtransmitter 26 or the connection cable 28.

It should be noted that the gateway 20 is composed of a modem 21, acontroller 22, and an interface 23 (a executing means).

The modem 21 is adapted to alternately convert a signal (analog) overthe public telephone line 2 and a signal (digital) in the controller 22such that information becomes transferable between the public telephoneline 2 and the controller 22.

The controller 22 is composed of a CPU (Central Processing Unit) 22 a (afirst extracting means, a second extracting means, a decoding means, andcertification means), a ROM (Read Only Memory) 22 b, a RAM (RandomAccess Memory) 22 c (a storage means), and a timer 22 d.

The CPU 22 a performs various computations and, at the same time,controls the other parts of the terminal 1-1. The ROM 22 b stores aprogram to be executed by the CPU 22 a and data necessary for theprocessing to be executed in the terminal. The RAM 22 c temporarilystores data and so on generated by the computation performed by the CPU22 a. The timer 22 d is adapted to output current time and date.

Referring to FIG. 3, there is shown a block diagram illustrating, by wayof example, a detailed constitution of the terminal 1-4 shown in FIG. 1.With reference to FIG. 3, components similar to those previouslydescribed with FIG. 2 are denoted by the same reference numerals andwill not be described any further.

As shown in FIG. 3, the terminal 1-4 has the generally the sameconstitution as that of the terminal 1-1 except that the IR transmitter26, the video deck 27, and the connection cable 28 are excluded.

The following describes the operation of the above-mentioned preferredembodiment.

It is assumed that a terminal installed in the home of a user is theterminal 1-1 shown in FIG. 2 and a terminal installed at place where theuser is working for example is the terminal 1-4 shown in FIG. 3.

The following describes processing to be executed when, in theabove-mentioned situation, the user sends an electronic mail from theterminal 1-4 installed in the workplace to the terminal 1-1 installed inthe home to reserve recording on the video deck.

Now, it is assumed that the input block 24 (the input means) of theterminal 1-4 shown in FIG. 3 has been operated and an electronic mailinput screen shown in FIG. 4 is displayed on the CRT monitor 25. In thisscreen, a RECEIVE button 30 at in the upper right corner of the screenis operated to receive an electronic mail. A SEND button 31 is operatedto send an electronic mail having a content entered in an input box 32.A password entry window 33 is displayed when the SEND button is pressedif the electronic mail includes a control command. It should be notedthat, in this password input window 33, as described later, a secret key(a password) necessary for encryption is inputted in an input box 34. AnOK button 35 in the window is operated to send the electronic mail by aninputted password. A CANCEL button 36 is operated to modify the contentof the electronic mail to be sent.

It should be noted that the password (secret key) is a keyconfidentially kept by each user in public-key encryption (in whichencoding and decoding are performed with keys of two types; a public keyand a secret key). The other key (namely, the public key) is held ineach terminal. Information encrypted by the secret key is decrypted bythe corresponding public key.

It is assumed here that the user has entered the information into thescreen shown in FIG. 4.

To be specific, line 1 of the input box 32 provides a destination “TO:”of the electronic mail. In this example, the destination is“home-server@bar.sony.co.jp”. It should be noted that “home-server”preceding “@” indicates the ID name of the terminal 1-1 to which thiselectronic mail is destined. The character string following “@”indicates a domain name (for example, the domain name of the provider3-1).

Line 2 provides the source “FROM:” of the electronic mail. In thisexample, the source is “foo@sm.sony.co.jp”, in which “foo” preceding “@”indicates the ID name of this user and “sm.sony.co.jp” following “@”indicates a domain name (for example, the domain name of the provider3-2).

Line 3 provides a second destination “Cc:” of the electronic mail. Inthis example, the second destination is “mother@sm.sony.co.jp”, in whichthis ID “mother” represents the ID name of the mother of this user forexample.

Line 4 provides the title “Subject” of this electronic mail. In thisexample, the title is “VIDEO Reservation”, which means reservation ofrecording on the video deck 27 shown in FIG. 2.

Next comes “VIDEO Reservation”, which is a control command forcontrolling the video deck 27, followed by characters for definingparameters for executing recording reservation. Namely, these charactersdefine to which parameters the numeric characters and alphabeticcharacters indicated below belong. In this example, the contents of thereservation are that channel (CH) 3 is to be recorded at standard (SP:Standard Play) speed (SPEED) from 11:00 (FROM) to 12:00 (TO) on the 10th(DATE). It should be noted that the order of these parameters may bechanged as required.

Next comes a message. In this example, message “PLEASE CHECK THERESERVATION” is inputted in this line, thereby transmitting theabove-mentioned setting to the mother of the user, to whom thiselectronic mail is destined.

The processing for the password input window 33 displayed below theabove-mentioned message will be described later.

If the SEND button 31 is pressed in the above-mentioned display screen,the inputted electronic mail is sent. The processing for sending theelectronic mail is executed by the processing shown in FIG. 5.

When the processing shown in FIG. 5 is executed, the CPU 22 a (theencoding means, the first additional means, and the second additionalmeans) of the terminal 1-4 determines, in step S1, whether the SENDbutton 31 has been pressed. If the SEND button 31 is found not pressed(NO), the CPU 22 a repeats the above-mentioned processing in step S1until the SEND button is pressed. If the SEND button is found pressed(YES), the processing goes to step S2.

In step S2, the CPU 22 a captures the parameters inputted through theinput screen shown in FIG. 4. In step S3, the CPU 22 a references thecaptured parameters to determine whether this electronic mail is forvideo reservation or not. If this electronic mail is found an ordinaryelectronic mail (NO), then, in step S4, the inputted information is sentas an ordinary electronic mail, upon which the processing comes to anend (END). If this mail is found to be for video reservation (YES), theprocessing goes to step S5.

In step S5, the CPU 22 a displays the password (the secret key) inputwindow shown in FIG. 4. Then, in step S6, the CPU 22 a determineswhether the CANCEL button 36 has been pressed or not. If the CANCELbutton 36 is found pressed (YES), then, back in step S1, the CPU 22 arepeats the above-mentioned processing. If the CANCEL button 36 is foundnot pressed (NO), the processing goes to step S7.

In step S7, the CPU 22 a determines whether the OK button has beenpressed or not. If the OK button is found not pressed (NO), then back instep S6, the CPU 22 a repeats the above-mentioned processing. If the OKbutton is found pressed (YES), the processing goes to step S8.

In step S8, the CPU 22 a captures the password (the secret key) inputtedin the box 34. It should be noted that this password is an 8-digitalphabetic and numeric character string such as “89U3578”.

In step S9, by use of the user secret key captured in step S5, the CPU22 a encrypts the mail address of the source of this electronic mail“foo@sm.sony.co.jp” and the parameters “10 11:00 12:00 3 SP” forrecording reservation. It should be noted that, for this encoding, apublic-key encryption algorithm (for example, the LUC algorithm) may beused.

In step S10, the CPU 22 a generates an electronic mail based on theinformation inputted in the screen shown in FIG. 4. Then, in step S11,the CPU 22 a adds the data encrypted in step S9 to the electronic mailgenerated in step S10 as user certification information. In step S12,the CPU 22 a sends the generated electronic mail added with thecertification information to the Internet 4 through the modem 21 (thesending means).

Referring to FIG. 6, there is shown a diagram illustrating, by way ofexample, the electronic mail sent as a result of the processing executedin FIG. 5. In this example, the destination mail address, the sourcemail address, the second destination mail address, the title of thiselectronic mail, the control command, the control parameters, and themessage inputted in the display screen shown in FIG. 4 are written inthis order. In addition, at the end of this electronic mail, thecertification information “ASASJK . . . CHXZC” generated in step S9shown in FIG. 5 is placed after header “EncryptedDATA-First”.

This electronic mail is sent to the provider 3-1 over the Internet 4 tobe stored in storage block, not shown, in the provider 3-1.

At this moment, the processing shown in FIG. 7 is being executed in theterminal 1-1, so that this electronic mail is received by the terminal1-1.

To be specific, the CPU 22 a determines in step S20 whether a presettime (for example, 10 minutes) has elapsed or not. If the preset time isfound not yet elapsed (NO), then still in step S20, the CPU 22 a repeatsthe above-mentioned processing until the preset time elapses. If thepreset time is found elapsed (YES), the processing goes to step S21.

In step S21, the CPU 22 a calls the provider 3-1 through the modem 21and determines whether the electronic mail addressed to the terminal 1-1has arrived. If the electronic mail is found not yet arrived (NO), then,back in step S20, the CPU 22 a repeats the above-mentioned processing.If the electronic mail is found arrived (YES), the processing goes tostep S22.

In step S22, the CPU 22 a captures the electronic mail from the provider3-1. Then, in step S23, the CPU 22 a extracts the certificationinformation (the information displayed at the end of the electronic mailshown in FIG. 6) from the captured electronic mail. Then, the processinggoes to step S24.

In step S24, by use of the corresponding public key, the CPU 22 adecrypts the certification information encrypted by use of the secretkey in the terminal 1-4. It should be noted that, in this decryption,the processing generally similar to the above-mentioned encryption maybe used.

In step S25, the CPU 22 a makes a comparison between the informationdecrypted by use of the public key, the source mail address“foo@sm.sony.co.jp” stored in the electronic mail, and the recordingreservation parameters “10 11:00 12:00 3 SP”. If no match is found (NO),then, back in step S20, the CPU 22 a repeats the above-mentionedprocessing. If a match is found (YES), the processing goes to step S26.

In step S26, the CPU 22 a reads all of the recording reservation datafrom the RAM 22 c and compares the read data with the reservationparameters included in the newly received electronic mail to determinewhether there is an overlap between the recording times in the recordingreservation data. If the recording reservation time is found overlapping(YES), then in step S27, the CPU 22 a sends an electronic mail notifyingthe terminal 1-4 of the overlap between the recording reservation times.Then, back in step S20, the CPU 22 a repeats the above-mentionedprocessing.

Referring to FIG. 8, there is shown a diagram illustrating, by way ofexample, the electronic mail that is sent in the processing of step 27.The electronic mail is sent to the terminal 1-4, so that the destinationis the user mail address “foo@sm.sony.co.jp” and the source is the mailaddress of the terminal 1-1 “home-server@bar.sony.co.jp”. The title ofthe mail is video reservation “VIDEO Reservation”, followed by thecommand for reservation and the reservation parameters in this order.Below this, a message telling failure of reservation “RESERVATION FAILEDBECAUSE RESERVATION DATA SENT AS ABOVE PARTIALLY OVERLAP WITH DATA OFRESERVATION NUMBER 1 IN RECORDING TIME” is written.

It should be noted that, if the recording reservation data is found notoverlapping (NO) in step S26, the processing goes to step S28.

In step S28, the CPU 22 a adds one to the number of pieces of recordingreservation data stored in the RAM 22 c and adds a resultant value tothe electronic mail as a reservation number and, at the same time, addsa message (to be described later) indicating that the reservation hasbeen accepted to the electronic mail. Consequently, an electronic mailas shown in FIG. 9 is generated. To be specific, in this example, thatan acceptance number (a temporary reservation number) is “1” isdisplayed after the title of this electronic mail. At the center of thiselectronic mail, acceptance of the reservation is displayed and amessage indicating an operation to be performed “TEMPORARY RESERVATIONMADE AS ABOVE. CHECK THE CONTENT AND RETURN FOR FIXED RESERVATION” isinserted. The electronic mail thus generated is sent to the terminal 1-4in step S29.

In step S30, the CPU 22 a sets a temporary reservation flag indicatingthat the recording reservation data is in temporary reservation state(to be described later) to “1”. In step S31, the CPU 22 a adds thistemporary reservation flag to the newly received reservation data andstores the resultant data into the RAM 22 c. Then, back in step S20, theCPU 22 a repeats the above-mentioned processing.

It should be noted that the temporary reservation state denotes thestate in which the recording reservation has been accepted for the firsttime. In this state, therefore, no recording operation is performed. Tostart a recording operation, the recording reservation data must betaken from the temporary reservation state into the fixed reservationstate.

The following describes the processing for taking the recordingreservation data from the temporary reservation state into the same intothe fixed reservation state.

Referring to FIG. 10, there is shown a flowchart for describing, by wayof example the processing to be performed in the terminal 1-4 whenreceiving the electronic mail sent in step S29 shown in FIG. 7.

Executing this processing, the CPU 22 a of the terminal 1-4 determinesin step S50 whether a preset time (for example, 10 minutes) has elapsedor not. If the preset time is found not yet elapsed (NO), then still instep S50, the CPU 22 c repeats the above-mentioned processing. If thepreset time is found elapsed (YES), the processing goes to step S51.

In step S51, the CPU 22 a closes the line with the provider 3-2 to makesure if the electronic mail to the terminal 1-4 has arrived. If no mailis found arrived (NO), then back in step S50, the CPU 22 a repeats theabove-mentioned processing. If the mail is found arrived (YES), theprocessing goes to step S52.

In step S52, the CPU 22 a captures the electronic mail from the provider3-2 through the modem 21 and stores the captured electronic mail intothe RAM 22 c at a predetermined area. Then, the processing goes to stepS53.

In step S53, the CPU 22 a displays the electronic mail stored in the RAM22 c onto the CRT monitor 25. As a result, an image shown in FIG. 11 forexample is displayed.

In the example shown in FIG. 11, the user mail address“foo@sm.sony.co.jp” is displayed as the mail destination. The mailaddress of the terminal 1-1 “home-server@bar.sony.co.jp” is displayed asthe mail source. The title of this mail is “VIDEO Reservation”,indicating that this mail is associated with video recordingreservation.

At the upper right of FIG. 11, the RECEIVE button 30 and the SEND button31 are displayed like those shown in FIG. 4. The CANCEL button 36 isdisplayed to the left of the RECEIVE button. The CANCEL button 36 isoperated to cancel the setting made this time.

Below the above-mentioned buttons, the reception number indicates thatthe information of the electronic mail sent by the previous operation(as shown in the screen of FIG. 4) has bee accepted (temporarilyaccepted) as the information of acceptance number 1. Immediately afterthis, the contents of the reservation are displayed. The message belowthis indicates that the temporary reservation has bee accepted andprovides information about an operation to be performed. At the bottom,the first certification information added in the previous sendingprocessing is displayed.

Referring to FIG. 10 again, the CPU 22 a of the terminal 1-4 determinesin step S54 whether the CANCEL button 36 has been pressed or not. If theCANCEL button 36 is found pressed (YES), the CPU 22 a ends theprocessing (END). If the CANCEL button 36 is found not pressed (NO), theprocessing goes to step S55.

In step S55, the CPU 22 a determines whether the SEND button 31 has beenpressed or not. If the SEND button 31 is found not pressed (NO), thenback in step S54, the CPU 22 a repeats the above-mentioned processing.If the SEND button 31 is found pressed (YES), the processing goes tostep S56.

In step S56, the CPU 22 a encrypts the acceptance number (“1” in thisexample) included in the electronic mail and the source mail address(“foo@sm.sony.co.jp” in this example) by use of the secret key inputtedin the display screen of FIG. 4. In step S57, the CPU 22 a adds thecertification information (refer to FIG. 6) added to the electronic mailsent from the terminal 1-1 to the electronic mail as the firstcertification information and, at the same time, adds the certificationinformation newly obtained in step S56 to the electronic mail as thesecond certification information, sending the resultant electronic mailto the terminal 1-1.

Consequently, the electronic mail as shown in FIG. 12 is sent from theterminal 1-4. Namely, in this example, the mail address of the terminal1-1 is written as the destination and the mail address of the user iswritten as the source. For the title, “VIDEO Reservation” is written,indicating that this electronic mail is associated with video recordingreservation.

On the next line, the acceptance number, the control command, and thereservation parameters are written. Below this line, the message sentfrom the terminal 1-1 is copied without change. Below this message, thefirst certification information (the same data as shown in FIG. 6,namely “Encrypted DATA-First”) and the second certification information(the data with the reservation number encrypted, namely “EncryptedDATA-Second”) are written.

The above-mentioned electronic mail is sent to the provider 3-1 over theInternet 4 to be stored therein.

Referring to FIG. 13, there is shown a flowchart for describing, by wayof example, processing to be executed in the terminal 1-1 when theelectronic mail sent from the terminal 1-4 is received.

Executing this processing, the CPU 22 a of the terminal 1-1 determinesin step S70 whether the preset time (for example, 10 minutes) haselapsed or not. If the preset time is found not yet elapsed (NO), thenstill in step S70, the CPU 22 a repeats the above-mentioned processing.If the preset time is found elapsed (YES), the processing goes to stepS71.

In step S71, the CPU 22 a closes the communication line with theprovider 3-1 and determines whether the electronic mail addressed to theterminal 1-1 has arrived at the provider 3-1. If the electronic mail isfound not arrived (NO), the CPU 22 a ends the processing (END). If theelectronic mail is found arrived (YES), the processing goes to step S72.

In step S72, the CPU 22 a reads the electronic mail that has arrived atthe provider 3-1 and stores this mail into the RAM 22 c at apredetermined area. Then, the processing goes to step S73.

In step S73, the CPU 22 a extracts the first certification information(“Encrypted DATA-First” shown in FIG. 12) and the second certificationinformation (“Encrypted DATA-Second” shown in FIG. 12) from the mailstored in the RAM 22 c. Then, in step S74, the CPU 22 a decrypts thefirst and second certification information by use of the public key. Theprocessing goes to step S75.

In step S75, the CPU 22 a makes a comparison between the firstcertification information decrypted by the public key, the source mailaddress, and the recording reservation parameters. The CPU 22 a alsomakes a comparison between the second certification informationdecrypted by the public key, the reservation number, and the source mailaddress. If a match is found (YES), it is determined that certificationhas been established. The processing goes to step S76. If no match isfound (NO), the CPU 22 a ends the processing (END).

In step S76, the CPU 22 a searches the RAM 22 a for specified recordingreservation data (the recording reservation data containing thereservation number written in the terminated electronic mail). If thespecified recording reservation data is not found (NO), then in stepS78, the CPU 22 a sends an electronic mail indicating that the specifiedreservation data has not been found to the terminal 1-4 and ends theprocessing (END). If the specified recording reservation data is found(YES), then in step S77, the CPU 22 a sets the temporary reservationflag to “0” to change temporary reservation to fixed reservation. Then,the processing goes to step S79.

In step S79, an electronic mail indicating that the reservation has beencompleted is sent to the terminal 1-4. FIG. 14 shows such an electronicmail by way of example. In this example, each of the user mail addressand the terminal mail address is written as the address of the source orthe destination. The title of the mail indicates that this mail is forvideo recording reservation. Below the title, the reservation number “1”is displayed, indicating that fixed reservation has been made with therecording reservation data shown below. Next comes a message“RESERVATION MADE AS ABOVE”, indicating that the recording reservationhas been made. Below this message, the first certification informationand the second certification information are written.

Receiving the above-mentioned electronic mail, the user knows that theelectronic mail sent before was accepted and the recording reservationhas been executed correctly.

When the processing of step 79 has been completed, the CPU 22 a ends theprocessing (END).

Referring to FIG. 15, there is shown a flowchart that describes thesequence of processing from sending of an electronic mail to completionof reservation. The following briefly describes this sequence withreference to FIG. 15. It should be noted that the right side of figureshows the sequence of processing to be executed in the terminal 1-1,while the left side shows the sequence of processing to be executed inthe terminal 1-4.

In FIG. 15, the input screen shown in FIG. 4 is displayed on theterminal 1-4, through which an electronic mail is inputted in step S90.At the same time, the secret key of the user is also inputted. The CPU22 a of the terminal 1-4 captures the mail address of the source and therecording reservation parameters from the inputted information by use ofthe above-mentioned secret key, encrypts the captured information, andadds the encrypted information to an electronic mail m1 as certificationinformation (refer to FIG. 6). The CPU 22 a sends the electronic mailthus generated to the terminal 1-1.

The terminal 1-1 receives the electronic mail m1 from the terminal 1-4and executes certification processing to determine whether the user whohas sent the electronic mail m1 is authentic or not. To be specific, theCPU 22 a of the terminal 1-1 extracts the certification information(“Encrypted DATA-First”) from the received electronic mail and decryptsthe extracted information by use of the public key. Then, the CPU 22 aextracts the source mail address and the recording reservationparameters from the electronic mail and compares the decryptedinformation with the extracted information to determine whether the userwho sent this mail is authentic (the user having the authorized secretkey), thereby executing certification.

If the certification has not been established (that is, if the sender ofthe electronic mail is not an authentic user), the processing goes tostep S92, ignoring the reservation specified by the electronic mail. Ifthe certification has been established, the CPU 22 a makes a comparisonbetween the newly sent recording reservation information and therecording reservation data stored in the RAM 22 c to check for data inwhich recording times overlap.

If the overlapping data is found, then in step S94, the CPU 22 a sendsan electronic mail m2 (refer to FIG. 8) indicating that the reservationis disabled to the terminal 1-4. Consequently, the terminal 1-4 knows bythis mail that the reservation is disabled.

If no overlapping data is found, then in step S95, the CPU 22 a adds thetemporary reservation flag set to “1” (indicative of the temporaryreservation state) to the recording reservation data and stores theresultant data into the RAM 22 c. Then, the CPU 22 a of the terminal 1-1adds the reservation number of the recording reservation data newlystored in the RAM 22 c and a message to an electronic mail m3 (refer toFIG. 9) and sends the resultant mail to the terminal 1-4.

The terminal 1-4 receives the above-mentioned electronic mail in stepS96, which is displayed as shown in FIG. 11. When the user presses theCANCEL button 36 in this screen, it indicates the previously madesetting is not approved by the user. The processing goes back to stepS90, in which the electronic mail is sent again. If the SEND button ispressed in the screen shown in FIG. 11, it indicates that the settinghas been approved by the user. The processing goes to step S98.

In step S99, the CPU 22 a of the terminal 1-4 extracts the source mailaddress and the reservation number of the received electronic mail andencrypts the extracted information by use of the secret key inputtedfrom the screen shown in FIG. 4. Then, the CPU 22 a adds the encryptedinformation as the second certification information and the information(the encrypted source mail address and reservation parameters) shown atthe bottom of FIG. 6 as the second certification information to anelectronic mail m4 (refer to FIG. 12) and sends the resultant mail tothe terminal 1-1.

In step 100, the terminal 1-1 receives this mail from the terminal 1-4.The CPU 22 a extracts the first certification information and the secondcertification information from the mail and decrypts the extractedinformation by use of the public key. The CPU 22 a compares the firstcertification information with the source mail address and thereservation parameters for certification. On the other hand, the CPU 22a compares the second certification with the source mail address and thereservation number for certification.

If the certification has not been established (that is, if no match isfound in the comparison in one or both of the first certificationinformation and the second certification information), then theprocessing goes to step S101, in which the specified data is held in thetemporary reservation state. On the other hand, if the certification hasbeen established, the CPU 22 a sets the temporary reservation flag addedto the specified recording reservation data to “0” to change temporaryreservation to fixed reservation. Then, the CPU 22 a sends an electronicmail m5 (refer to FIG. 14) indicative of completion of the reservationand ends the processing. The terminal 1-4 receives this mail m5 to knowthat the reservation has been completed.

Thus, certifying the sender of the electronic mails by use of thecertification information prevents unauthorized control of the electricdevices by the electronic mails sent by parties other than the authenticuser.

The following describes the recording processing to be executed on theterminal 1-1.

By the above-mentioned sequence of processing, the first recordingreservation data sent from the outside terminal 1-4 is stored in the RAM22 c of the home terminal 1-1 to be put in the temporary reservationstate. Further, the second electronic mail is sent and, when temporaryreservation is changed to fixed reservation, the CPU 22 a of theterminal 1-1 controls the video deck 27 according to the processingshown in FIG. 16, starting recording at a reserved time.

Executing the processing shown in FIG. 16, the CPU 22 a of the terminal1-1 compares the output data of the timer 22 d with the fixedly reservedrecording reservation data stored in the RAM 22 c in step S120 todetermine whether the recording start time has come or not. If therecording start time is found not yet reached (NO), then still in stepS120, the CPU 22 a repeats the above-mentioned processing. If therecording start time is found reached (YES), the processing goes to stepS121.

In step S121, the CPU 22 a determines whether the video deck 27 isconnected by cable or not. To be specific, the CPU 22 a determineswhether the video deck 27 is connected to the gateway 20 by theconnection cable 28. If the video deck 27 is found connected by cable(YES), the processing goes to step S122. If the video deck 27 is foundnot connected by cable (NO), the processing goes to step S129.

In the preferred embodiment shown in FIG. 2, the video deck 27 isconnected to the gateway 20 by both cable and the IR transmitter 26. Inthis case, connection by the connection cable 28, which is higher intransfer rate and reliability than the IR transmitter 26, is preferred.

Referring to FIG. 16 again, if the decision is YES in step S121, then instep S122, the CPU 22 a powers on the video deck 27 through cabledinterface (namely, the connection cable 28). The, in step S123, the CPU22 a sets the recording speed according to the recording reservationdata (for example, sets the recording speed to SP mode) through thecabled interface.

In step S124, the CPU 22 a sets the recording channel in the video deck27 through the cabled interface according to the recording reservationdata. Further, in step 125, the CPU 22 a sends a predetermined controlsignal to the video deck 27 through the cabled interface, startingrecording.

In step S126, the CPU 22 a compares the output data of the timer 22 dwith the recording end time in the recording reservation data stored inthe RAM 22 c to determine whether the recording end time has come. Ifthe recording end time is found not yet reached (NO), then still in stepS126, the CPU 22 a repeats the above-mentioned processing until therecording end time comes. If the recording end time is found reached(YES), then in step S127, the CPU 22 a stops recording on the video deck27 through the cabled interface. Then, in step S128, the CPU 22 a powersoff the video deck 27 and returns to step S120 to repeat theabove-mentioned processing.

If, in step S121, the video deck 27 is found not connected by cable(NO), then in step S129, the CPU 22 a sends a predetermined controlsignal through the IR interface (namely, the IR transmitter 26),powering on the video deck 27.

Next, in step S130, the CPU 22 a sets the recording speed according tothe recording reservation data through the IR interface.

In step 131, the CPU 22 a compares the output data of the timer 22 dwith the recording reservation data stored in the RAM 22 c to determinewhether the recording end time has come. If the recording end time isfound not yet reached (NO), then in step 133, the CPU 22 a repeats theabove-mentioned processing until the recording end time comes. If therecording end time is found reached (YES), then in step S134, the CPU 22a stops the video 27 through the IR interface. Next, in step S135, theCPU 22 a power off the video deck 27 and returns to step S120 to repeatthe above-mentioned processing.

According to the above-mentioned processing, the video deck 27 can becontrolled according to the recording reservation data stored in the RAM22 c, thereby recording a desired program.

As described, the above-mentioned preferred embodiment allows the userto control electric appliances such as a video deck installed in home bysending an electronic mail from a terminal outside home. At the sametime, the user can check whether a specified electric appliance can beset remotely and confirm the control settings by sending an electronicmail.

According to the above-mentioned preferred embodiment, if thereservation contents overlap (for example, recording times overlap), thereservation information received later is ignored, resulting exclusivecontrol, which can prevent duplicate reservation and contradiction inreservation from happening.

In the above-mentioned preferred embodiment, the video deck 27 is usedfor example as an electric device which is controlled by the gateway 20.It will be apparent that the present invention is not restricted to thevideo deck and therefore applicable to any other electric devices suchas air conditioner and a audio device.

In the above-mentioned preferred embodiment, the terminals 1-1 through1-6 are interconnected through the Internet 4 and the providers 3-1 and3-2. It will be apparent that the terminals can also be interconnectedby other transmission media.

In the above-mentioned preferred embodiment, public-key encryption isused. It will be apparent that secret-key encryption (also calledcommon-key encryption) may also be used.

Japanese Patent Application Number 09064230 filed on Mar. 18, 1997,discloses a similar receiver controlled by Network Protocol. Thisapplication is owned by the assignee of the present invention and thecorresponding US application is still pending.

While the preferred embodiments of the present invention have beendescribed using specific terms, such description is for illustrativepurposes only, and it is to be understood that changes and variationsmay be made without departing from the spirit or scope of the appendedclaims.

1. A computer-implemented method for controlling a video recordingdevice over a network that is performed without using interiorcomponents of the video recording device, the computer-implementedmethod comprising: using a computer on a user side of the network toperform steps including, inputting information to generate at least aportion of an electronic mail, encrypting predetermined information, afirst adding step of adding information encrypted in said encryptingstep to said electronic mail generated in said inputting step ascertification information, a second adding step of adding to saidelectronic mail a control command to control a reservation function ofthe video recording device to reserve an operation time thereof,transmitting through the network said electronic mail with saidcertification information added in said first adding step and saidcontrol command added in said second adding step and receiving anelectronic mail indication from the network that no reservation for therequested operation time has been made when there is an overlap of therequested operation time with any previously entered operation times;and using a computer on a video recording device side of the network toperform steps including, receiving said transmitted electronic mail fromthe network at a location of the video recording device, a firstextracting step of extracting said certification information from saidreceived electronic mail, a second extracting step of extracting saidcontrol command from said received electronic mail, decrypting saidcertification information extracted in said first extracting step usinga public key, certifying whether a sender of said electronic mail is anauthorized user by referencing said certification information decryptedin said decrypting step, determining if the control command extracted inthe second extracting step is seeking an operation time duplicating onealready reserved and transmitting an electronic mail on the networkindicating that no reservation has been made because the control commandextracted in the second extracting step is seeking a duplicate operationtime of one already reserved, storing said control command extracted insaid second extracting step if said sender of said electronic mail hasbeen certified in said certifying step to be an authorized user, and ifthe determining step determines there is no duplicated operation timerequest, and controlling said reservation function of the videorecording device to reserve an operation time thereof based on saidcontrol command stored in said storing step.